As is perhaps well known, tubular surgical drains used in draining after an abdominal surgery have presented a long outstanding problem of effectiveness of drainage versus comfort of the wearer. Mechanically, the problem has been that tubular drains, if thin walled so as to be pliable and, therefore, more comfortable, collapse under body pressures and forces exerted upon them or at the surgical cut as the healing process occurs with swelling and, later, as the swelling goes down, the inside surfaces of such tubes tending to stick together or, become kinked and blocked so that drainage is not effected at the desired rate. On the other hand, if the tubular length is more rigid or reinforced the tube is uncomfortably situated in an area which is sore and painful because of the operation. The problem has been approached as in U.S. Pat. No. 1,596,754 to Moschelle, dated 1926 by providing reinforcing ribs to prevent collapse of the tube, the ribs being longitudinally extending and being circumferentially thick and with sides which do not extend perpendicularly from the tube wall so as to be relatively thick at the rib base, as in the round tube with thick ribs, as in the round tube with a thick rib in which a longitudinal passageway which never collapses because of thick walls is defined and in which thick spiral ribs may be provided. Such thick ribs have proven to be uncomfortable. Representative later efforts are illustrated (a) by the patent dated in 1963 to Coburn, U.S. Pat. No. 3,112,746, which utilizes a tube of smaller diameter within the column of a larger diameter tube, and (b) the patent dated 1969 to Abramson, which utilizes relatively rigid tubular stock within an outer more pliable tube.
Generally, it is seen that the art is confronted with the problem of a comfortable drain which is flexible and pliable but which, nevertheless, does not collapse so as to remain open for drainage.